The invention further relates to a method for operating an insufflation system.
An insufflation system of this kind is known from WO 2007/050516 A and such a valve is known from DE 10 2009 048 994 A1.
Insufflation systems are used in the medical field for the purpose of inflating hollow cavities in the body, such that endoscopic procedures, for example inspections or interventions, can be carried out in the body cavities with a better view.
Inspections of this kind are, for example, examinations of the gastrointestinal tract, for example in preventive medical examinations of the rectum and large intestine. Another widespread area of use is laparoscopy of the abdominal space.
An insufflation system of this kind consists, in the first instance, of a medical instrument that can be inserted into the body cavities and that has a channel through which an insufflation gas can be guided from the proximal end to the distal end. The insufflation gas is made available by an insufflator, which is connected to the proximal end of the medical instrument during use.
The insufflator supplies the instrument with a defined volumetric flow that is suitable for the respective procedure, i.e. a defined amount of insufflation gas is moved through the instrument by the insufflator. The so-called flow rate is usually given in l/min. At the same time, a defined insufflation pressure can be set, so as to be able to adapt this to the respective anatomical circumstances.
Air was initially used as insufflation gas, but it was found that air is poorly resorbed by the body, and postoperative effects are caused by the high nitrogen content of the air.
Therefore, air is increasingly no longer used as insufflation gas and is replaced by other gases, in particular carbon dioxide (CO2), which can be very quickly resorbed by the living body and can be eliminated in the breath.
Therefore, within the meaning of the present invention, the term “insufflation gas” refers to those gases that are suitable for insufflation of body cavities, but not to air.
Carbon dioxide as insufflation gas is unproblematic from the medical point of view and can also be delivered in relatively large quantities to the body, even in protracted examinations or interventions. However, the carbon dioxide that can be used in the medical field is relatively expensive.
In an actual insufflation procedure, i.e. the inflation of body cavities, quantities of insufflation gas of, for example, 1-3 l/min are delivered at pressures of approximately 350 mmHg.
In the so-called standby mode, for example approximately 5 l/min are delivered at a pressure of approximately 80 mmHg.
In the insufflation system mentioned at the outset, the various states are controlled by means of a so-called bypass valve being arranged in the channel of the instrument. This bypass valve has, firstly, a passage arranged in the flow path of the channel. Secondly, a branch line leading to the environment is present in the valve. This branch line ends in a head of a manually movable valve head piece and the mouth of this branch line lies in the area of the head.
In a first switching state of the valve, this branch line is open. That is to say, insufflation gas delivered from the insufflator flows through the branch line and therefore escapes to the environment through the valve. The channel within the medical instrument is still open, but it provides a remarkable flow resistance to the approaching insufflation gas. As a result the insufflation gas flows through the branch line in the valve to the environment and not through the channel distally to the valve. That corresponds to the standby mode.
The valve is designed such that the outlet opening of the branch line can be closed when a person holding and operating the instrument places a finger on the opening. By closing the branch line, only the channel in the instrument is open. The gas now has to flow through a long and mostly thin flow channel to the patient, for which reason a greater resistance has to be overcome. The higher flow resistance causes a pressure increase in the system.
This corresponds to the second switching state of the valve, in which it is now possible for the insufflation gas from the insufflator to be passed exclusively through the channel of the instrument.
When the outlet opening of the branch line of the valve is freed again by removing the finger that was closing it, the insufflation gas can again be discharged to the environment via the valve. The pressure in the system then drops again. These pressure differences can be used to identify the different switching states of the first valve.
However, a disadvantage of such an insufflation system is that the relatively expensive insufflation gas, in particular carbon dioxide, flows continuously out of the system via the valve in the instrument in the first switching state and is thus lost for the actual insufflation procedure. Consequently, measures have to be taken to reduce these quantities of carbon dioxide that are lost.
US 2012/0016293 A1 discloses an endoscope gas delivery system having a carbon dioxide gas cylinder for delivering the insufflation gas. When the remaining amount of the carbon dioxide gas of the cylinder is detected and the detected pressure of the carbon dioxide becomes less than a predetermined value an air pump is rotated to supply pressurized air to the body.
It is therefore an object of the present invention to remedy this situation and to further develop an insufflation system in such a way that it can be operated more economically and more safely, in particular with savings being made in terms of expensive insufflation gas.